During an invasive procedure, a clinician is concerned about the location and trajectory of an invasive device inserted into a patient. The clinician needs to clearly understand exactly where the invasive device is located and how it is positioned for both patient safety and clinical effectiveness.
There are multiple techniques that are currently used for determining the position of an invasive device. The invasive device may be tracked with an electromagnetic tracking system. The electromagnetic tracking system provides real-time feedback about the position of the invasive device, but it requires significantly more equipment. For example, the electromagnetic tracking system requires an electromagnetic field generator that is positioned outside the patient and one or more sensor coils attached to the invasive device being tracked. Electromagnetic fields are susceptible to distortion that may arise from environmental factors such as electrical equipment and/or conductors positioned near that patient and/or the field generator.
Another conventional technique involves obtaining position information from an X-ray fluoroscopy system. The X-ray fluoroscopy system may either be on during the whole procedure or it may be turned on only during periods of time where the clinician adjusts the position of the invasive device. Either way, the X-ray fluoroscopy system exposes both the patient and the clinician to ionizing radiation. Additionally, the images provided by an X-ray fluoroscopy system only contain 2D data. As such, it may be difficult for the clinician to accurately determine the position of the invasive device, particularly when it is moved in a direction that is out-of-plane of the X-ray fluoroscopy image. While this drawback may be partially overcome by obtaining X-ray fluoroscopy images at multiple different angles, it is still difficult for the clinician to understand the exact position of the invasive device based on data from a X-ray fluoroscopy system.
A commonly used technique to guide minimally invasive procedures is to combine two different imaging modalities. For example, X-ray fluoroscopy may be used for overview and invasive device visualization, while 3D ultrasound may be used for detailed anatomical structure assessment and 3D navigation. When two different imaging modalities are used in combination, it is important for the user to understand their relation to each other. This can be achieved by image-overlay or aligned side-by-side views. Generating such views is only possible if the relative position and orientation between the two images of different modalities are known.
For these and other reasons an improved system and technique for tracking the position of an invasive device is desired.